The document is a list of 158 terms related to relativity and cosmology. It includes concepts from both special and general relativity as well as cosmological models and observations. Some of the terms listed are the Bianchi identity, Big Bang, cosmological redshift, Einstein's field equations, Friedmann models, Galilean transformation, Hubble's law, length contraction, light cone, Lorentz transformations, Michelson-Morley experiment, relativistic mechanics, simultaneity, special relativity, and twin paradox.